A brief and witty statement which is apparently self - contradictory is called -

Epigram: (তীক্ষ্ণ, বুদ্ধিদীপ্ত বা ব্যঞ্জনাময় উক্তি; ক্ষুদ্র শ্লেষসমৃদ্ধ কবিতা বিশেষ।)
A brief and witty statement which is apparently self - contradictory.
Ex:
'Our sweetest songs are those that tell of saddest thought'.
Here, Sweetest and Saddest oppose each other but as we go beneath the surface level.

Paradox: (কূটাভাস; যে উক্তি আপাতদৃষ্টিতে স্ববিরোধী মনে হলেও সত্যবর্জিত নয়)
A self-contradictory statement that hides a rational meaning.
Ex: 'Sweet are the uses of adversity'.

Source: An ABC of English Literature - Dr M Mofizar Rahman